1. Field of the Invention
An inner face seal is arranged in a face or front surface of a piston rotating upon an eccentric of a rotary piston engine. The seal has a base body that is U-shaped in axial cross section thereof. The seal includes arms or legs forming two sealing rings, that include end surfaces which slide along and against the adjoining sidewall and which are effective as sealing surfaces subject to contact pressure exerted via spring action. A bore in this sidewall coaxial to the eccentric shaft is partially polished, buffed or abraided by an inner sealing surface of the seal during rotation of the piston.
2. Description of the Prior Art
Such an inner face seal has a purpose to prevent the passage of fluid cooling medium and lubricating medium from the gearing or power (gear) transmission and piston mounting or bearing chamber into the working or operating chambers. The leakage fluid penetrating into the space or chamber between the two sealing rings is conveyed in a crescent-shaped segment or section of the opening coaxial to the eccentric shaft in the housing sidewall polished, buffed or abraided by the seal.
Such an inner seal and especially the manner of operation or effectiveness of such a seal can be found described in German Pat. No. 12 16 042--Bentele et al issued Nov. 24, 1966 corresponding to U.S. Pat. No. 3,171,590--Bentele et al dated Mar. 2, 1965. German Pat. Nos. 22 02 899--Eiermann issued May 20, 1980 corresponding to U.S. Pat. No. 3,816,041--Eiermann dated June 11, 1974 and 25 50 889--Eiermann issued May 23, 1986 corresponding to U.S. Pat. No. 4,080,120--Eiermann dated Mar. 21, 1978, both belonging to the assignee of the present invention, describe such inner seals which have transverse webs or crossbars between the legs of the U-shaped foundation or base body forming individual chambers. A return or running-back of the oil is prevented or hindered upon the side of the sealing ring that is not polishing, or buffing or abraiding the bore or opening in the housing sidewall. Sealing rings which run against the sidewalls with the surfaces of the legs and intermediate crosspieces or bars are described by these German Patents. Of course there is guaranteed or assured with the two last-mentioned patents that these surfaces are ground smooth and consequently always engage in a flat planar or surface-to-surface relationship. However there cannot be hindered or prevented that an oil film is maintained under these butting faces and in this manner residue or remainder of oil still can enter into the working or operating chambers. The requirements consequently cannot be adequately and sufficiently fulfilled with such seals for attaining cleanliness of the exhaust gases with motors or engines to be free of combustion products of the oil or for the compressed or pressurized air delivered by the compressors to be free of oil.
An object of the present invention is to provide a still further improved oil separation from the housing sidewalls via the present inventive seal.
This object, and other objects and advantages of the present invention, will appear more clearly from the following specification in conjunction with the accompanying drawings.